The structures that remain separate with forming a layer is

Options

A. Epithelial cells
B. Muscle cells
C. Nervous cells
D. Glands

Answer

To solve the question "The structures that remain separate with forming a layer is", we will analyze each of the provided options step by step.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for structures that do not combine to form a layer. We need to identify which of the given options fits this description.

2. **Analyzing Option A: Epithelial Cells**:
- Epithelial cells are known to form layers that line surfaces of the body, both internally and externally.
- They are tightly packed and create a continuous sheet, often supported by a basement membrane.
- **Conclusion**: This option is incorrect because epithelial cells do form layers.

3. **Analyzing Option B: Muscle Cells**:
- Muscle cells (or myocytes) are responsible for movement and are organized into muscle tissue.
- While they can be grouped together, they do not form a continuous layer in the same way epithelial cells do.
- **Conclusion**: This option is incorrect because muscle cells do not remain separate in a way that fits the question.

4. **Analyzing Option C: Nervous Cells (Neurons)**:
- Neurons are specialized cells of the nervous system that transmit signals.
- They are unique in that they do not form layers; instead, they exist as individual cells that communicate with each other through synapses.
- **Conclusion**: This option is correct because neurons remain separate and do not form a layer.

5. **Analyzing Option D: Glands**:
- Glands are made up of epithelial cells that are specialized for secretion.
- They can form structures that may appear as layers, especially in glandular tissues.
- **Conclusion**: This option is incorrect because glands do not fit the criteria of remaining separate.

### Final Answer:
The correct answer is **Option C: Nervous Cells (Neurons)**, as these structures remain separate and do not form a layer.